High efficiency power supplies are highly desirable for battery-operated systems, including mobile phones, tablets, laptops and other mobile user devices. For example, displays for such devices often need very high efficiency along with low output ripple and fast transient response. In addition, many battery-powered devices include circuitry requiring supply voltages in excess of the battery voltage, and hence boost conversion is necessary. Although relatively high efficiencies are possible using standard boost DC to DC converter circuits, these supply circuits suffer from high switched current output noise. Large output capacitors can be used to control output ripple, but this increases product size, cost and weight. In addition, standard boost DC to DC converters may suffer from right half plane zeros, which limits the available converter bandwidth for stable operation.